Vial a small
proportion of Spirit of Hartshorn or Urine, and finding that upon this
affusion, the Tincture immediately recovers its Caeruleous Colour, I am
thereby confirm'd firm'd in my former Opinion, of the Sulphureous Nature of
these Salts. And so, whereas it is much doubted by Some Modern Chymists to
what sort of Salt, that which is Praedominant in Quick-lime belongs, we have
been perswaded to referr it rather to Lixiviate than Acid Salts, by having
observ'd, that though an Evaporated Infusion of it will scarce yield such a
Salt, as Ashes and other Alcalizate Bodyes are wont to do, yet if we
deprive our Nephritick Tincture of its Blewness by just so much Distill'd
Vinegar as is requisite to make that Colour Vanish, the _Lixivium_ of
Quick-lime will immediately upon its Affusion recall the Banished Colour;
but not so Powerfully as either of the Sulphureous Liquors formerly
mention'd. And therefore I allow my self to guess at the _Strength_ of the
Liquors examin'd by this Experiment, by the _Quantity_ of them which is
sufficient to Destroy or Restore the Caeruleous Colour of our Tincture. But
whether concerning Liquors, wherein neither Acid nor Alcalisate Salts are
Eminently Praedominant, our Tincture will enable us to conjecture any thing
more than that such Salts are not Praedominant in them, I take not upon me
to determine here, but leave to further Tryal; For I find not that Spirit
of Wine, Spirit of Tartar freed from Acidity, or Chymical Oyl of
Turpentine, (although Liquors which must be conceiv'd very Saline, if
Chymists have, which is here no place to Dispute, rightly ascrib'd tasts to
the Saline Principle of Bodyes,) have any Remarkable Power either to
deprive our Tincture of its Caeruleous Colour, or restore it, when upon the
Affusion of Spirit of Vinegar it has disappear'd.

_EXPERIMENT XI._

And here I must not omit, _Pyrophilus_, to inform You, that we can shew You
even in a Mineral Body something that may seem very near of Kin to the
Changeable Quality of the Tincture of _Lignum Nephriticum_, for we have
several flat pieces of Glass, of the thickness of ordinary Panes for
Windows one of which being interposed betwixt the Eye and a clear Light,
appears of a Golden Colour, not much unlike that of the moderate Tincture
of our Wood, but being so look'd upon as that the Beams of light are not so
much Trajected thorough it as Reflected from it to the Eye, that Yellow
seems to degenerate into a pale Blew, somew